Practice Stamps For Math Problems: one addition stamp, one subtraction stamp, 2 bottles of ink Interesting School Supplies:The teaching stamp set as fun as toys, makes learning fun and exciting, increase children's interest in learning ! suitable for students to practice, parent guidance, teacher teaching Save Time: Easy to operate ,the math questions can appear in front of you by scrolling the stamp, which can be adjusted, and the questions can be changed by gently twisting the button, and the questions will be randomly selected. Good Quality: photosensitive process, clear stamping, Print thousands of impressions without losing the original quality,Strong ABS plastic components and housing. Refill Pack: Durable,Equipped with 2 Free refills ink, open the oil cap and drop 5-6 drops at once